Solar control film

ABSTRACT

A solar control film for application to window glass comprises a vapor deposited aluminum coat, which partially transmits light, interposed between a pair of moisture permeable polymeric strata, each of which is self supporting. In one modification, an optional outer coat on one of the polymeric strata is composed of a pressure sensitive adhesive in association with a silicone release sheet. In another modification, an optional outer coat on the other of the polymeric strata is composed of a silicone release agent.

' United State Windorf 11 51 Nov. 27, 1973 SOLAR CONTROL FILM Michael E.Windorf, Malden, Mass.

[73] Assignee: Material Distributors Corporation,

Woburn, Mass.

[22] Filed: Feb. 8, 1971 [21] Appl. No.: 113,426

[75] Inventor:

[52] US. Cl 161/4, 161/1, 161/6, 161/167,161/406, 350/1, 156/99, 161/165[51] Int. Cl. B44f 1/100, A611 15/06 [58] Field of Search 350/1, 316,166, 350/164;156/99,l00;161/1, 4, 6,167,165

[56] References Cited UNITED STATES PATENTS 2,882,183 4/1959 Bond et a1.161/167 3,073,734 1/1963 Bemmels 161/167 3,681,179 8/1972 Theissen 161/43,069,301 12/1962 Buckley et a1.... 156/99 3,398,040 8/1968 Allen et al.350/1 3,170,833 2/1965 Noyes 161/6 3,410,625 11/1968 Edwards 350/13,499,697 3/1970 Edwards 156/99 3,429,733 2/1969 Wolf et a1. l6l/lPrimary Examiner(3eorge F. Lesmes Assistant Examiner-R. J. RocheAttorney-Morse, Altman & Oates [57] ABSTRACT A solar control film forapplication to window glass comprises a vapor deposited aluminum coat,which partially transmits light, interposed between a'pair of moisturepermeable polymeric strata, each of which is self supporting. In onemodification, an optional outer coat on one of the polymeric strata iscomposed of a pressure sensitive adhesive in association with a siliconerelease sheet. In another modification, an optional outer coat on theother of the polymeric strata is composed of a silicone release agent.

2 Claims, 4 Drawing Figures POLYESTER ADHESIVE VAPOR DEPOSITED ALUMINUMPOLYESTER PATENTEDHUVZ? I975 3,775,226 SHEET 1 BF 2 POLYESTER ADHESIVEVAPOR DEPOSITED ALUMINUM Pmmmuvzmm 3.775226 SIILEI 2 OF 2 RELEASECOATING POLYESTER ADHESIVE APOR DEPOSITED ALUMINUM POLYESTER LOPTICALLYCLEAR PRESSURE SENSITIVE AQUEOUS DETERGENT APPLIED TO DEACTIVATEPRESSURE SENSITIVE STRATUM SOLAR CONTROL FILM BACKGROUND AND SUMMARY Thepresent invention relates to a solar pg nt r l film to PP iQQ;LLALQ QQANn-QLQQL9. F lRFHW Sion thfihmugllof rars txisiblsan; lttsxisalst adiationfrom"tlie ed u ction of infrared transmission'liiriits i'iiterior heating in the summer and interior cooling in the winter.Reduction of visible light transmission limits uncomfortable glare. Andreduction of ultraviolet transmission limits fabric fading and finishcracking of furniture. Solar control film is intended to reflect solarinfrared and ultraviolet and still to permit excellent visibility withminimum distortion. It has been found that 100 square feet of su ch filmhas a comparasulation that is partially transparent. Difficulties havebeen encountered in storing such films compactly and in laminatingand'maintaining such films in superposition on windows.

A typical prior solar control film comprises a polymeric sheet, a vapordeposited aluminum coat, a protective polymeric coat, and a pressuresensitive coat, which is deactivated initially by the presence of anagent that eliminates tack during storage, as well as during the timethe film is being applied to a window. Just before the film is appliedto the window, the pressure sensitive adhesive coating is subjected towater, in consequence of which the agent is dissolved and the pressuresensitive adhesive is reactivated to produce a final bond when dry. Whenmoistening the pressure sensitive adhesive, the water is intended towash away all of the water soluble agent. But, this washing step isnever complete so that some agent always remains. In consequence, thebond between the film and the window can be ruptured when ambientmoisture penneates into the interface between the film and the window.Another drawback of this structure is that the protective polymeric coattends to crack, ripple and rupture whereby deterioration of the aluminumcoat occurs.

The primary object of the present invention is to provide a solarcontrol film comprising a vapor deposited aluminum coat, which is of athickness characterized by a light transmission of 5 to 50 percent,interposed between a pair of moisture permeable polymeric strata, eachof which ranges in thickness from one fourth to 1 mil so as to beindividually self supporting. It has been found that the self supportingstrata eliminate physical and chemical degradation that typically occursat the vapor deposited aluminum coat in prior systems. In onemodification of the solar control film, an optional integral outer coaton one of the polymeric strata is composed of a pressure sensitiveadhesive in association with a discrete silicone release sheet. Inanother modification, an optional integral outer coat on the other ofthe polymeric strata is composed of a silicone release agent. In suchmodifications, storage in roll form is permitted by the incompatibilityof the pressure sensitive adhesive and the silicone release agent,application to the window glass is enabled by a water compatible detackifier which is applied to the pressure sensitive adhesive, andpermanent implacement is achieved by permeation of the water compatiblede-tackifier through the film and via the edges.

Other objects of the present invention will in part be obvious and willin part appear hereinafter.

The invention accordingly comprises the products and processes, togetherwith their components, steps and interrelationships, which areexemplified in the accompanying disclosure, the scope of which will beindi' cated in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of thenature and objects of the present invention, reference is made to thefollowing detailed description, taken in connection with theaccompanying drawings, wherein:

FIG. 1 is a flow diagram illustrating a solar control film, inexaggerated cross section, undergoing a process of the presentinvention;

FIG. 2 illustrates an architectural window incorporating the presentinvention;

FIG. 3 is a flow diagram illustrating an alternative solar control film,in exaggerated cross section, undergoing a process of the presentinvention; and

FIG. 4 illustrates the solar control film of the present inventionrolled for storage and transport.

DETAILED DESCRIPTION Generally, the solar control film of FIG. 1comprises, in laminated sequence, a moisture permeable polymericstratum12, a bonding stratum 14, a vapor deposited aluminulrl'istratum l6, anda moisture permeable polymeric stratum 18. All of these strata exceptthe alumirium stratum are optically clear and transparent. The aluminumstratum is optically clear and partially radiation transmitting,partially radiation absorbing and par tially radiation reflecting.Typically: moisture permeable polymeric strata 12 and 18 are composed ofa polyester such as that sold under the trademark Mylar a polyesterterephthalate, by Dupont; vapor deposited aluminum stratum 16 isproduced by controlled density, vacuum vapor deposition upon the surfaceof polymeric stratum l8; and adhesive bonding stratum 14 is coated uponeither vapor deposited aluminum stratum 16 or polymeric stratum 12 as athin film immediately before superposing the polymeric films and causingthe adjacent surfaces to adhere. Typically, polymeric strata l2 and 14each ranges in thickness from one-fourth to 1 mil, preferably beingapproximately one-half mil, adhesive stratum l4 ranges in thickness from0.0001 to 0.0003 inch preferably being approximately 0.0002 and vapordeposited aluminum stratum 14 is characterized by a visible lighttransmission of 5 percent to 60 percent, having a thickness of no morethan 300 angstrom units. Adhesive stratum 14 is cast from a ketonicand/or alcoholic solution of a therrnosetting polyester or acrylateester, the solution preferably being applied to the clear film prior tosuperposing of the two poly meric films in the formation of the finalproduct. For example, the polyester is Mylar, the acrylic is a methyland/or ethyl methacrylate, the ketone is methyl ethyl ketone and thealcohol is toluol. The resulting film has a pleasant, soft grey colorthat permits excellent visibility.

As shown in FIG. 1, an aqueous solution of an adhesive 20 is applied tostratum 18 during application of solar control film 10 to a window 24.During superposition of the solar control film upon window 24, theadhesive serves as a lubricant to permit smoothing of the film andelimination of air .pockets between the film and the window by means ofa squeegee 28. Following application of the film to the window, thewater of the adhesive diffuses through the film and the edges of theinterface between the film and the window. In other words, preferablyall of the strata of the film are selected for their vapor permeability.

In one form, stratum 12 is composed of a weatherable, ultraviolet lightabsorbing polymer effective in the range of from 200 to 380 nanometers,that does not darken or decompose upon prolonged exposure'to intenseultraviolet. For example, such as polymer is a weatherable polyestercontaining, as an ultraviolet absorbent, a dispersed substitutedbenzophenone of the type sold by Antara Chemicals under the trademarkUvinul. FIG. 3 illustrates an architectural glass window 34, theexterior surface of which is laminated to a solar control film 32, ofwhich stratum 18 is contiguous with and stratum 12 is remote from window34.

Generally, the solar control film of FIG. 4 comprises, in laminatedsequence, a release stratum 40, a moisture permeable polymeric stratum42, a bonding stratum 44, a vapor deposited aluminum stratum 46, amoisture permeable polymeric stratum 48, and a pressure sensitiveadhesive stratum 50. All of these strata except the aluminum stratum areoptically clear and'transparent. The aluminum stratum is optically clearand partially radiation transmitting, partially radiation absorbing, andpartially radiation reflecting. Typically: release stratum 40 iscomposed of a silicone; moisture permeable polymeric strata 42 and 48are composed of a polyester such as that sold under the trademark Mylarby Dupont; vapor deposited aluminum stratum 46 is produced by controlleddensity vacuum vapor deposition upon the surface of polymeric stratum48; adhesive bonding stratum 44 is coated upon either vapor depositedaluminum stratum 46 or polymeric stratum 42 as a thin film immediatelybefore superposing the polymeric films and causing the adjacent surfacesto adhere; and pressure sensitive adhesive 50 is composed of a mixtureof synthetic and natural rubbers, e.g., neoprene and latex, a tackifiersuch as terpene, and an organic solvent such as toluene. Typically,release stratum 40 has a thickness ranging from 0.0001 to 0.001 inchpreferably being 0.0005 inch, polymeric strata 42 and 44 each has athickness ranging from one fourth to 1 mil, preferably being one halfmil, adhesive stratum 44 has a thickness of ranging from 0.0001 to0.0003 inch, preferably being 0.0002 inch, vapor deposited aluminumstratum 44 is characterized by a light transmission of percent to 60percent and has a thickness of no more than 300 angstrom units, andpressure sensitive adhesive stratum has a thickness ranging from I to1.5 mil, preferably approximately 1.25 mil. Adhesive stratum 44 is castfrom a thermosetting polyester or acrylic in ketone and/or toluolsolution, preferably being applied to the clear film prior tosuperposing of the two polymeric films in the formation of the finalproduct. The resulting film has a pleasant, soft grey color that permitsexcellent visibility.

As shown in FIG. 3, an aqueous detergent 52 is applied to pressuresensitive adhesive 50in order to deactivate the pressure sensitiveadhesive during application of solar control film 38 to a window 54.During superposition of the solar control film upon the window shown at54, the aqueous detergent coat 52 serves as a lubricant to permitsmoothing of the film and elimination of air pockets between the filmand the window.

Following application of the film. to the window, the aqueous detergentdiffuses through the edges of the interface between the film and thewindow and through the film itself. In order to facilitate thisevaporation process, preferably all of the strata of the film areselected for their vapor permeability, the pressure sensitive adhesivestratum 50, in particular being vapor permeable but insoluble withrespect to water. In other words, the detergent is polar and thepressure sensitive adhesive is non-polar. The detergent permeates towardthe edges of the film glass laminate and also penetrates through thefilm by diffusion but without reaction with or solution into thepressure sensitive adhesive. The arrangement is such that a separaterelease sheet is eliminated. The silicone release stratum on the outsideserves as a lubricant when the film is laid down with a squeegee 58 andalso serves as a protective coating to prevent scratches when the filmis washed after being laminated in place. The thin film vapor coating ofaluminum stops solar radiation from passing through the glass so thatmuch of the heat is gone before it can be absorbed by the glass itself.The mirror effect that reflects the suns rays outwardly also reflectsartificial heat inwardly for lower winter heating costs.

FIG. 4 illustrates a roll of the sheeting of FIG. 1 with its releasecoating 50 at one face and its pressure sensitive coating 52 at theother face, coiled so that pressure sensitive adhesive stratum 52 is incontact with release stratum 53 for storage and transport. In analternative embodiment, release coating 50 is omitted and a separatesilicone release sheet is superposed on pressure sensitive adhesivestratum 52 until use. In another alternative embodiment, adhesivestratum 44 contains a colorant, preferably a dye, which results in aneasily selected hue.

The present invention thus provides an improved solar control film thatis less costly, can be more simply stored and transported, more easilyapplied to a window and more permanently used on interior or exteriorwindow surfaces. Since certain changes may be made in the abovedisclosure without departing from the scope of the invention thereof, itis intended that all matters shown in the accompanying drawings ordescribed in the foregoing specification be interpreted in anillustrative and not in a limiting sense.

What is claimed is:

1. A flexible solar control film sheet for adherence to a glass window,said solar control film comprising:

a. a first polyester self-supporting stratum'ranging in thickness fromone-fourth mil to 1 mil, said first polyester self-supporting stratumbeing optically clear and transparent to visible light;

b. a second polyester self-supporting stratum ranging in thickness fromone-fourth to 1 mil, said second polyester self-supporting stratum beingoptically clear and transparent to visible light;

c. an inner bonding stratum between the adjacent faces of said firstpolyester self-supporting stratum and said second polyesterself-supporting stratum, said inner bonding stratum being composed of apolymer selected from the class consisting of polyesters and acrylateesters;

d. a vapor deposited aluminum stratum on a face of one of said firstself-supporting polyester stratum and said second self-supportingpolyester stratum in contact with said bonding stratum, said vapordeposited aluminum stratum having a thickness of g. at least one of saidpolyester self-supporting strata containing an ultraviolet lightabsorbing polymer effective in the range of 200 to 380 nanometers; h.said inner bonding stratum ranging in thickness from 0.0001 to 0.0003inch.

2. The flexible solar control film sheet of claim I, wherein said outeradhesive stratum is composed of a mixture of natural and syntheticrubbers, a tackifier and an organic solvent.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 775226 Dated November 27 1973 Inventor g Michael E.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

On page 1, line 2, cancel "Windorf" and insert-Willdorf-;

line 4, cancel "Windorf" and insert--Willdorf-.

Signed and Scaled this Nineteenth Day of October 1976 [SEAL] Arrest.-

RUTH C. MASON C. MARSHALL DANN Arresting ()fj'iver Commissioneruj'lalenlx and Trademarks

2. The flexible solar controL film sheet of claim 1, wherein said outeradhesive stratum is composed of a mixture of natural and syntheticrubbers, a tackifier and an organic solvent.